Archived posting to the Leica Users Group, 2001/03/20
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Theoretically, any diffractive material not at the lens center can cause focus shift; gels are so thin they cause no significant focus shift when behind or ahead of the lens center. Jack _____________ - ----- Original Message ----- From: leica@rakitzis.com To: leica-users@mejac.palo-alto.ca.us Sent: Tuesday, March 20, 2001 5:49 PM Subject: [Leica] Re: 12mm Heliar UW Just wondering about filters in the back... They cause some focus shift, right? Which if you are shooting in a reflex or view camera is no problem, just refocus with the filter in place. But with a rangefinder I have to wonder if this is going to be a factor. Furthermore, isn't the depth of focus narrower with wide-angle than with tele lenses (the opposite of DOF)? Without any hard evidence to support this, I would also share some of Tom's concern about putting a filter behind a super wide angle lens on a rangefinder camera. Byron.